SLI IS Nvidia's pride and joy. It used to belong to 3DFX and now it is Nvidia's treasure. Therefore Monday will be the day for Nvidia, as R580, Radeon X1900 XT Crossfire edition with another X1900 XTX card will outperform Nvidia's GTX 512 SLI in almost every single case. It runs faster in games and synthetic 3Dmark benchmarks.